Author Topic: $20 LCR ESR Transistor checker project  (Read 3408321 times)

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Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #3275 on: February 18, 2017, 07:10:43 pm »
I tried to power on the tester with the atmega pins relative to the test points 1/2/3 lifted. It still displaying "battery?" but now is around 1800mV
Even with this pins lifted and some components removed, 5v still preset on the TP 1.

With the resistors for probe #1 removed and the MCU pins lifted you could check for any shorts. I'm not sure but the 1800mV might be ok when the MCU pin (PC0 for probe #1) is floating.
« Last Edit: February 18, 2017, 07:12:30 pm by madires »
 
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Offline mateusps

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Re: $20 LCR ESR Transistor checker project
« Reply #3276 on: February 18, 2017, 07:32:31 pm »
Thanks madires! I'm still looking for shorts on the board.

@Strada916

I've posted hi res photos on imgur and a video

http://imgur.com/a/p5uXU


 

Offline Strada916

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Re: $20 LCR ESR Transistor checker project
« Reply #3277 on: February 18, 2017, 07:51:48 pm »
Some of the joints need a little more solder. Otherwise it's ok.

Sent from my D6503 using Tapatalk

The Bone, the Off-White, the Ivory or the Beige?
 
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Offline timelessbeing

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Re: $20 LCR ESR Transistor checker project
« Reply #3278 on: February 19, 2017, 05:34:42 am »
A pull-up resistor at PC4 (ATmega 328) and the BJT's base resistor should be replaced by a higher value. The MCU uses PC4 as input for measuring the reference voltage and as open collector output for switching the relay.

I used 22K for my base resistor. If I use 220K for the pull-up, that will allow 21uA to always flow to my BJT, which I think will turn it on a little bit. Can I use a higher value pull-up? Like 5 meg to make sure the transistor stays off when it's not needed?
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #3279 on: February 19, 2017, 12:49:51 pm »
I used 22K for my base resistor. If I use 220K for the pull-up, that will allow 21uA to always flow to my BJT, which I think will turn it on a little bit. Can I use a higher value pull-up? Like 5 meg to make sure the transistor stays off when it's not needed?

The relay is operated in reversed logic, i.e. the relay short circuits the probes when not switched on. For switching the relay you want to drive the BJT into saturation. Therefore the pull-up resistor plus the base resistor in series have to pass enough current to do that. At the same time you have to make sure that the voltage at the connection of both resistors (PC4) is not around 2.5V to prevent the tester from thinking it's an external 2.5V reference (k-firmware). And the pull-up resistor should be as high as possible to limit the current through the MCU when PC4 is switched to low.
 
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Offline 1413

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Re: $20 LCR ESR Transistor checker project
« Reply #3280 on: February 19, 2017, 09:51:47 pm »
For those who have the same kit like mine, which is known as AY-AT kit, I fixed user interface here and there for best use with rotate encoder. Almost all functions leave untouched

- Based on version 1.26m
- Press down and hold -> menu
- When icon power on/off appears on bottom right corner, rotate left -> restart, rotate right -> menu, press button -> turn off
- Change Zener to Vext because this kit doesn't have the hardware to do it.
- If you want zener measurement, use external voltage
- Update makefile to work with USBtinyISP

Thanks madires for a wonderful job
« Last Edit: February 20, 2017, 10:17:37 am by 1413 »
 
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Offline madcat

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Re: $20 LCR ESR Transistor checker project
« Reply #3281 on: February 20, 2017, 01:46:59 pm »
I'm very happy that it's finally starting to work, but you need to need to give it at least one more go with water (try to dry it as quickly as possible!) and then alcohol. Clean very thoroughly. You'll probably also want to clean between the pins of the MCU, too (just in case). Just make sure it's completely dry before powering up the board, and, of course, be gentle enough not to damage anything while you're at it.
i'm not confident enough to clean it with water yet, especially with rotary encoder, zif&atmel socket, and DC jack is still soldered onboard. does it safe to do that (clean with water)?

Madcat,
i have a bag of n-mosfets i puchased from ebay that show as double diodes and that is bcause they are  :(
there are all sort of fake components out there so be careful.
Before start testing unknown components make sure you test a set of known good components.  :)
thank you for the information. i didn't know that those fake components exist in ebay. must be more aware when buy them next time.
but in my case, i think it is my tester which have false reading about the mosfets, because i've run some manual tests on them with DMM (refers to some youtube tutorials), my mosfets really are mosfets, not dual-diode, and they acts as they should in circuit.

is it possible that i have some customized firmware in my atmega chip that not functions normally as the original one?
or maybe i need to redo the soldering and clean each of the components from old flux residue that might unreachable when i cleaned them while still soldered onboard, like the bottom of zif&atmel sockets?
 

Offline hapless

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Re: $20 LCR ESR Transistor checker project
« Reply #3282 on: February 21, 2017, 05:54:04 am »
or maybe i need to redo the soldering and clean each of the components from old flux residue that might unreachable when i cleaned them while still soldered onboard, like the bottom of zif&atmel sockets?

If nothing else works, you may have to. But I would do so only as a last resort.

is it possible that i have some customized firmware in my atmega chip that not functions normally as the original one?

If you didn't flash it yourself, the answer is, "Who knows!" But I think in this case it's unlikely.

i'm not confident enough to clean it with water yet, especially with rotary encoder, zif&atmel socket, and DC jack is still soldered onboard. does it safe to do that (clean with water)?

I'm not telling you to put it into a bucket of water and leave it there overnight. Use a little on a toothbrush. Tap water is somewhat alkaline in most places. This will help neutralize the acid. Then you immediately clean the same spot with alcohol. I have not had any electronic components rust on me just yet after this.

I never quite know what is encompassed under "toolchain" when people refer to it; does "toolchain" include "make" executables too, because if Arduino IDE contains a "toolchain" (well I know it contains "avr-gcc.exe" etc) then it doesn't appear to include "make.exe".

That's because it's different for different projects. For our purposes, the default definition of a toolchain would probably be whatever Atmel thinks it is.
« Last Edit: February 21, 2017, 06:03:21 am by hapless »
 
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Offline madcat

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Re: $20 LCR ESR Transistor checker project
« Reply #3283 on: February 22, 2017, 03:12:57 pm »
after did 3-passes of IPA "bath", brushed it with toothbrush concentrated at bottom of zif&atmel sockets body, i think my tester is working normally now! yeaahhh!
now it able to detect mosfets&transistors correctly, quite precise at capacitor, resistor&voltage measurements.  :-+

thank you to all who helped me solved my problem. this community is awesome!   :clap:
 

Offline Pukker

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Re: $20 LCR ESR Transistor checker project
« Reply #3284 on: February 22, 2017, 10:47:16 pm »
For those who have the same kit like mine, which is known as AY-AT kit, I fixed user interface here and there for best use with rotate encoder. Almost all functions leave untouched

- Based on version 1.26m
- Press down and hold -> menu
- When icon power on/off appears on bottom right corner, rotate left -> restart, rotate right -> menu, press button -> turn off
- Change Zener to Vext because this kit doesn't have the hardware to do it.
- If you want zener measurement, use external voltage
- Update makefile to work with USBtinyISP

Thanks madires for a wonderful job

Hi 1413,
Can you post the compiled files please.
8 and or 16 Mhz.
Thanks.
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #3285 on: February 23, 2017, 08:20:47 pm »
Please find 1.27m in the SVN. Besides several smaller improvements the new version has an alternative PWM gen for testers with a rotary encoder, a servo checker and support for PCF8574 based LCD packpacks. The I2C framework allows to add other I2C clients quite easily. BTW, I've dropped the edition name, so it's just 1.27m.
 
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Offline mauroh

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Re: $20 LCR ESR Transistor checker project
« Reply #3286 on: February 24, 2017, 03:03:11 pm »
Hi Markus I just compiled the 1.27m for my M12684 DIY Kit and noticed something strange on the Servo test function:
If I select 50Hz sweep mode I see on the display:
Servo
*2944ms
  50Hz <->

I don't have a servo connected, but looking at the output signal is doing some sweep...
If I turn the rotary encoder slowly of one step, the sweep speed jumps to 89.21ms, if I go back up it reach 2944ms after some random increments.
I guess the firmware is trying to change the sweep speed dividing it in half, in half again and so on, but looks like it jumps alot.
M'I wrong?

Within next Monday I should perform some tests with the morors I have and will give you some feedback.
Thank you so much

BTW, I tryed also the Opto Coupler test function ant it is really cool!!

Mauro
« Last Edit: February 28, 2017, 01:21:12 pm by mauroh »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #3287 on: February 24, 2017, 03:42:39 pm »
If I turn the rotary encoder slowly of one step, the sweep speed jumps to 89.21ms, if I go back up it reach 2944ms after some random increments.

The change should be related to the turning speed of the encoder. In extras.c in function Servo_Check() there's following code:
Code: [Select]
    /* consider rotary encoder's turning velocity */
    Step = 1;
    if (Enc.Velocity > 1)          /* larger step */
    {
      Step <<= Enc.Velocity;       /* 2^velocity */
    }

Enc.Velocity is in the range of 1 to 7 based on the turning speed. You could try to replace the code above with something like this:
Code: [Select]
   Step = Enc.Velocity;

Do you got that issue just with the servo check or also with other tests?
 

Offline timelessbeing

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Re: $20 LCR ESR Transistor checker project
« Reply #3288 on: February 25, 2017, 05:17:50 am »
If anybody needs, Electronics Goldmine has some authentic TEXTOOL gold plated ZIF sockets for $2.
http://www.goldmine-elec-products.com/prodinfo.asp?number=G22009
It's cam lock, rather than lever lock, which might work better for people who want enclosures.

 
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Offline bitseeker

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Re: $20 LCR ESR Transistor checker project
« Reply #3289 on: February 25, 2017, 06:22:18 am »
That cam lock is pretty neat. I suppose one could 3D print a knob to fit in it for use in an enclosure.
TEA is the way. | TEA Time channel
 

Offline 1413

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Re: $20 LCR ESR Transistor checker project
« Reply #3290 on: February 25, 2017, 10:59:37 am »
For those who have the same kit like mine, which is known as AY-AT kit, I fixed user interface here and there for best use with rotate encoder. Almost all functions leave untouched

- Based on version 1.26m
- Press down and hold -> menu
- When icon power on/off appears on bottom right corner, rotate left -> restart, rotate right -> menu, press button -> turn off
- Change Zener to Vext because this kit doesn't have the hardware to do it.
- If you want zener measurement, use external voltage
- Update makefile to work with USBtinyISP

Thanks madires for a wonderful job

Hi 1413,
Can you post the compiled files please.
8 and or 16 Mhz.
Thanks.

Open readme.txt for how to compile in windows 10.
Anyway, I attach the compiled hex and epp files
« Last Edit: February 25, 2017, 11:03:50 am by 1413 »
 
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Offline indman

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Re: $20 LCR ESR Transistor checker project
« Reply #3291 on: February 25, 2017, 07:13:46 pm »
Since the ST7735 isn't extremely slow, you could try and move the power-on section in LCD_Init() to the end. Maybe just LCD_Cmd(CMD_DISPLAY_ON), and removing MilliSleep(120).

Hi, madires!
Once again I want to thank you for excellent operation!
Would like to pay attention to some questions in operation of a firmware to AY-AT kit.
The display in case of start has a garbage. If to use your council which I quoted then this problem disappears.
I very much liked the fact that you offset symbols of elements on lateral face. It will allow to use a font with higher resolution for displays 128x64!
I used in case of compilation of a firmware symbols with permission 30x32.
It well looks on the display with permission 160x128.
One more request to you - whether add options will be involved in config.h which I marked on a screenshot?
« Last Edit: February 25, 2017, 07:16:06 pm by indman »
 
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Offline javagerms

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Re: $20 LCR ESR Transistor checker project
« Reply #3292 on: February 25, 2017, 08:38:16 pm »

i got the EZM LCR meter. but I'm puzzled.
the LCD pcb has 9 holes, but i got only 8 male pins connector.  on the main pcb, it has 9 female slots.
so should align on the left or to the right.
thanks!
 

Offline Pukker

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Re: $20 LCR ESR Transistor checker project
« Reply #3293 on: February 25, 2017, 09:14:27 pm »

pen readme.txt for how to compile in windows 10.
Anyway, I attach the compiled hex and epp files

Yes, you are right, I have to learn compiling myself,
but, very thanks for your great and usefull help.
« Last Edit: February 25, 2017, 09:19:41 pm by Pukker »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #3294 on: February 26, 2017, 12:23:32 pm »
One more request to you - whether add options will be involved in config.h which I marked on a screenshot?

I'll add a configuration switch for the ST7735 initialization. HW_ADJUST_CAP and  HW_CAP_RELAY are two hardware options for the ATmega 664/1284 based circuit. The first one is a fixed film cap plus 470k resistor for the adjustment procedure. And the latter is for connecting a fixed cap in parallel to the test pins when using SamplingADC. So you don't have to connect a cap manually. But both options aren't implemented yet in the m-firmware.
 
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Offline cfoek

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Re: $20 LCR ESR Transistor checker project
« Reply #3295 on: February 26, 2017, 03:19:00 pm »
Thankfully the maker of my LCR-T4 tester had the good sense to mark the ISP port for programming - the legend is UNDER the LCD, you just need to de-solder the LCD backlight LED and lift... and you see it. I've also taken a photo of the LCD ribbon cable on my model, for what it matters - it may help someone:







Out of interest, how does one find out what type of LCD/driver chip/interface is used, per tester variant, please? Thanks.

hello , I also bought this tester have you successful flashing the hex and epp files ?
mine flash successful use hex and epp from http://www mikrocontroller net/ , but when i push the button display blank only with led turn on

if you successeful flash this tester what firmware did u use and what program did you use ?

oh i use sinaprog 2.1 with usbavr china clone 

thanks

Edit :
ups sorry did not read carefully on your post on previous page , i will try  on your firmware that u post (mega328_T3_T4_st7565_SmallerTypeface_Menu_edits)

will report back thanks
« Last Edit: February 27, 2017, 06:37:06 pm by cfoek »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #3296 on: February 26, 2017, 05:40:39 pm »
In most cases it's some other LCD controller or the default contrast needs to be changed.
 

Offline waspinator

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Re: $20 LCR ESR Transistor checker project
« Reply #3297 on: February 26, 2017, 06:57:52 pm »
has there been any effort to write an open source firmware for these type of modules?
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #3298 on: February 26, 2017, 07:22:36 pm »
Both firmware versions (k & m) support a multitude of display controllers, all open source.
 

Offline upsss

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Re: $20 LCR ESR Transistor checker project
« Reply #3299 on: February 27, 2017, 06:36:04 am »
Hi, is there some sort of a detailed description of the differences/advantages/disadvantages between the k & M version of the firmware?
« Last Edit: February 27, 2017, 07:50:44 am by upsss »
 


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